Gas and liquid contact apparatus



Dec. 17, 1963 MACROW ETAL GAS AND LIQUID CONTACT APPARATUS Filed Jan.14, 1960 FIG. I

INVENTORS:

LAWRENCE MACROW MARTIN M. VAN ADELSBERG ATTORNEY.

nits

Sttes atent Olice 3,114,786 GAS AND LllQlUll) NTACT APRARATU LawrenceMarrow, Fayetteville, and Martin M. Van

Adelsherg, Syracuse, N.Y., assignors to Carrier Corporation, Syracuse,N.Y., a corporation of Delaware Filed Jan. 14, 1%9, Ser. No. 2,491 4(Ilaims. (tCl. 261-24) This invention pertains to gas and liquid contactapparatus and more particularly to an improved liquid distributionsystem for use in such apparatus.

In lvlunters Patent No. 2,809,818, granted October 15, W57, there isdisclosed cooling tower structure including a packing, means for passinggas through the packing, and a rotary sprayer for distributing waterover the packing. The packing may be composed of alternate corrugatedand plain sheets attached at their points of contact to provide aplurality of adjacent parallel cells of relatively small cross-sectionalareas between the flat an undulating folds of the sheets so that liquidcan bridge the Walls of the cells by surface tension. Means are providedon the packing to break the bridging of the liquid. The undulating foldsof the corrugated sheets provide the spacing of the partition walls ofeach cell, and the edge portions of the assembled sheets provide a largearea through which liquid enters and leaves the packing. The sheets arepreferably composed of paper possessing qualities of high moistureabsorbency and a large degree of wet strength. "i moisture absorbencyincreases the elfectiveness of the packing in heat transfer.

The rotary sprayer for distributing Water over the packing includes aplurality of arms with spaced openings therein. The sprayer subdividesthe stream of supply water into droplets which are sprayed over thepacking. The heavier droplets discharged from the sprayer contact thetop of the packing and flow downwardly therethrough by gravity, however,the smaller droplets discharged from the sprayer may be caught up in theair stream and discharged from the cooling tower. To remove the smallerdroplets suspended in the air stream before it leaves the tower,eliminator plates are often provided in the cooling tower over therotary sprayer.

Previous rotary Sprayers required drilling or" closely spaced holes inthe arms thereof. The diameter of the holes constantly increased fromthe center of the sprayer to the extremity of the arms. This method offorming the openings in the sprayer arms is costly. Too, the smallopenings tend to become clogged with foreign matter in use and reducethe eficiency of the cooling tower as a result of unequal wetting of thepacking.

The chief object of this invention is to provide gas and li uid contactapparatus in which these disadvantages or defects in prior constructionsare obviated.

An object of the invention is to provide gas and liquid contactapparatus including an improved sprayer which assures a uniformdistribution of water over the top of the packing.

A further object of the invention is to provide an improved sprayarrangement for gas and liquid contact apparatus which obviates the needfor eliminator plates.

Another object of the present invention is to provide an improvedsprayer for use in gas and liquid contact apparatus which uniformly wetsthe top of the packing and which is adjustable for various water flowrates, and can therefore equalize density of distribution regardless ofthe area wetted.

A still further object is to provide an improved sprayer having anelongated slot extending substantially the length thereof that caneasily be cleaned.

This invention relates to gas and liquid contact apparatus and includesin combination a casing, a packing in the using comprised of a series ofclosely spaced wall memhers defining cells open at the top and bottomadapted to be moistened from above, the cross-sectional area of eachcell being so small that liquid can bridge the walls of the cell bysurface tension, and means on the packing for breaking the bridging ofliquid, means for passing a gas stream through the packing, and meansfor distributing a liquid over the packing comprising a sprayerrotatably mounted in the casing above the packing closely adjacent thetop thereof, the sprayer including a hub adapted to be connected to asource of liquid, at least one tubular sprayer arm connected to the hub,the rain having a slot therein extending substantially the lengththereof, means for adjusting the width the slot, to affect a uniformdistribution of liquid over the top of the packing and bafile meansconnected to the arm extending substantially coextensive with the slotto redirect splashing liquid to the top surface of the packing.

The attached drawings disclose a preferred embodiment of the inventionin which:

FIGURE 1 is a sectional view of a cooling tower embodying the presentinvention;

FIGURE 2 is a bottom view on an enlarged scale of ti o improved rotarysprayer;

PZGURE 3 is an enlarged transverse sectional view through the sprayerarm taken along the line ill-HI of FIGURE 2, with parts being omitted;

FIGURE 4 is a sectional view showing the relationship of the deflectorto the arm of the water distributor.

Referring to the drawings, there is disclosed in FIG URE l, a coolingtower employing the present invention. This cooling tower 5 includes acasing 5 mounted on support members s. Along the lower portion of thecasing and extending substantially around the entire casing are suitablelouvers '7, which permit air to pass into the lower portion of thecasing. In the extreme lower portion of the casing is located a suitablesump 8 wherein water is collected. The water level is maintained at adesired height by means of the supply line in which is connected asuitable valve ll operated by float 311 in the sump.

Packing 12, preferably of the type disclosed in lVinntcrs Patent No.2,809,818, is mounted above the sump S and louvers '7. This packing 12is supported by suitable means such as rods or angle irons 13 which aresecured to the inside of casing 5.

Above the packing is mounted water distributor or rotary sprayer 14-. inthe preferred embodiment, this water distributor comprises hub 15 and aplurality of arms 16 each having a slot 17 extending substantially thelength thereof. These arms are in fluid communication with hub 15 whichis rotatably mounted above bearing assembly 16. Each arm 1% has aremovable cover 3-6 on the outer end thereof to permit access to theinterior of the arm to clean the same and has a flange 31!. connected onthe other end thereof. Slots 32 are formed in the flange to permi rotaryadjustment of arm 16 with respect to hub Suitable bolts 33 extendthrough each slot 32 and connect flange 31 to hub l5. Normally each armis secured to hub 15 so that slot 17 is at an angle to the verticalwhereby the reaction of the water leaving slot 17 in arm 16 will rotatethe water distributor l4. Rotation of arm 16 with respect to hub 15 willchange the angle of discharge of the water leaving the slot from about 5to The greater the angle of discharge or more nearly the slot approachesthe horizontal, the greater will be the thrust. As a consequence, thedistributor is will rotate faster.

if desired, motor means may be incorporated in bearing assembly 18. Themotor means may comprise a small turbine which rotates the hub andpasses water into the arms 16 from whence the Water is discharged ontopacking 12.

Water is introduced in bearing assembly 18 through supply or riser pipe19 from the place where it is used F and the coo-led water falls in thesump 3 and is conducted i from the sump to the place of use.

Suitable fan means 21 are mounted in the upper porltion 'of the casing 5to draw air through the packing in *he'git exchange relation with waterpassing therethrough. he cooled water collects in sump d and isdischarged herefrom through conduit 29 to the place where it is used.Pump means (not shown) are provided to force the water through conduits19 and 20.

FIGURE 2 discloses a bottom View of water distributor or rotary sprayerl4. Baflle 22. is suitably secured to arm in as for example, by bolt 23,and extends substantially over the length thereof. If desired, bafile 22may be integrally made from a plate or from sheet metal, however, it ispreferred that baffle 22 be made in parts; a first rigid part 24preferably sheet metal, connected to said arm and a second resilientpart 2.5 as for example, rubber, connected at the rear of the firstrigid part by screws 449. Part 24 includes a downwardly bent portion 24'the end of which in normal operation is closely adjacent the top surfaceof packing 12. Though only two arms are shown connected to the hub 15,it will be apparent that one or more arms may be employed as desired.

Rotary sprayer M is mounted closely adjacent the top of packing 12 asseen in FIGURE 3. The tendency for the water to splash and be caught upin the upwardly moving air stream is resisted by bafile 22 which trapsthe splash water and redeposits it on the top of packing 12. Thus, thenecessity for the series of eliminator plates commonly used in coolingtower of this type to remove the splash water from the air streamdischarged from the cooling tower is obviated.

Slot 17 is generally tapered towards the hub as best seen in FlGURE 2 toobtain a uniform wetting of the surface of the packing. A progressivelygreater quantity of water is discharged along the length of each arm.The highest efficiency of evaporative cooling is attained when an equalquantity of water is discharged upon each increment of surface area ofpacking 3.2. The width of the slot 1'7 at a given distance R from theaxis of rotation of the sprayer is determined by the following formula:

where:

W=the width or". the slot at point 11 taken at R distance from the axisof rotation of the sprayer, expressed in inches.

Dn:=twice the distance taken from the axis of the supply pipe to point)1, expressed in inches.

D;z=twice the distance taken from the axis of the supply pipe to pointIt, a minute distance from point It. G=design fiow rate of water ingallons per minute per square foot of top surface of packing l2.

Ps initial static pressure supplied in supply pipe at entrance to armltd, expressed feet of Water. N desired revolutions per minute of thesprayer.

Adjustment means 26 may be uniformly spaced along the arm 16 to taperslot 17 and to vary the width of :slot 17 along the length thereof. Thewidth of the slot :at each adjustment means may be calculated from the:aboe formula and the adjustment may be made at the "time offabrication. The slot gradually widens and then narrows somewhat nearthe extremity of arm i6. By virtue of the unique conformation of slot 17an equal quantity of water is discharged upon each square inch ofsurface area of packing 12 regardless of the water flow rate through thesprayer, which may be from one to ten gallons of water per minute persquare foot of top surface area of packing 12 depending upon designconsiderations. Normally when the cooling tower is part of a mechanicalrefrigerating system, the flow rate may vary from 3 to 8 gallons perminute per square foot of 4 top surface area of packing 12 and when thecooling tower is part of an absorption refrigeration system, the flowrate may vary from 1 to 4 gallons per minute per square foot of topsurface of packing 12.

Each adjustment means 25 is preferably cor of bolt 27 extending throughopenings and A) in arm to and having external threads on an end thereofand nut 3t? having complementary internal threads therein. As is readilyapparent, by rotating nut 33 in one direction, the walls of sprayer armto are drawn together narrowthe slot, and by rotating nut 3t? in theopposite direction the walls of arm 1d are permitted to move apartwidening slot 17. For clarity, only three adjustment means have beenshown in each arm. Obviously the number of adjustment means used will bedependent upon the length of arm M.

if desired each adjustment means may be comprised of a bolt extendingtnough a hole in arm 16 at one side of slot 17, said bolt having threadson the other end thereof adapted to be screwed into a threaded hole inarm E6 on the other side of the slot. Turning the bolt in one directionwould draw the walls of the arm closer together narrowing the slot andturnin the bolt in the opposite direction would permit widening of theslot.

Water discharged from the portion of the slot adjacent supply pipe 19woul have an outward force component and thus the packing surfaceadjacent supply pipe 1.9 might not be uniformly moistened. To assurethat the packing surface immediately adjacent supply pipe 1? ismoistened, a deflector plate 35 is fixed in each arm about one-half inchfrom the beginning of slot 17.

The arm may be fabricated from a length of standard pipe or tube havinga slot cut therein or from a flat sheet rolled so that the opposite endsare closely adjacent one anolher to form a slot.

An advantage of the improved rotary sprayer is the ease of cleaning thetapered slot. By inserting a narrow knife-like tool in the slot adjacentthe hub and drawing said tool toward the end of arm 16, the slot can bereadily cleaned. Further, cover 36 may be removed to facilitate cleaningthe inside of each arm 16.

In operation, water is pumped through supply pipe 19 to hub 15. Thereactive force of water issuing from tapered slot 17 rotates the sprayerl4 and effects a uniform distribution of water over the surface ofpacking l2. Deflector plate 35 directs a small portion of water flowingin arm 16 onto the surface of packing 12 adjacent pipe 19 to assurewetting said surface. T e water flows downwardly by gravity through thecells formed by the closely spaced wall members of packing l2 and formsa film on the wall members. Fan means 21 causes air to be drawn throughlouvers '7 into casing 5 and up through packing 12 in counterflowrelation to the water to effect evaporative cooling thereof. This isdone at the cost of evaporating approximately two percent of the Waterpassed through the packing. The cooled water collects in sump 8 and isremoved therefrom through conduit 29 to the place where it is used.

Water issuing from slot 1! strikes the surface of the packing andsplashe In the absence of ballle 22 the splash water would be picked upin the air stream and discharged from the cooling tower. This wouldnecessitate drawing more water through supply line 9 and would increasethe operational costs of the cooling tower. P rt 24 is initiallyadjusted so that the lower tip of bent portion 24' is approximatelyone-half inch from the surface of packing 112. Most of the splash wateris deflected back to the packing surface by part 24 and portion 24'. Theremainder of the splash water is redirected to the packing surface byresi cnt part 25 which can trail on the top of packing 12. Because ofthe upwardly moving air stream, part 25' contacts the surface of packing12 only lightly or flutters adjacent the surface of packing 12 as thedistributor ltd rotates.

While we have described a preferred embodiment of the invention, it willbe understood that the invention is not limited thereto since it may beotherwise embodied within the scope of the claims.

We claim:

1. In a gas and liquid contact apparatus, the combination of a packing,means for passing a gas stream through said packing, liquid supplymeans, and means for distributing the liquid over said packing to flowtherethrough in contact with the gas stream passing therethrough, saiddistributing means comprising a sprayer rotatably mounted above saidpacking adjacent the top thereof, means for rotatably mounting saidsprayer, said sprayer including a tubular arm having a slot thereinextending substantially the length thereof and placed in the lowerportion thereof to discharge liquid from the arm toward the packing,said liquid supply means communicating with the interior of said tubulararm, and adjustment means for tapering the width of said slot toward theaxis of rotation of the sprayer whereby the liquid discharged from saidslot is uniformly distributed over the top of the packing, saidadjustment means including a plurality of bolt means spaced from eachother longitudinally of the arm for adjusting the Width of the slot.

2. A gas and liquid contact apparatus according to claim 1 in whichbaffie means are provided extending substantially coextensive with theslot therein to redirect splashed liquid onto the top of said packing,said baflle means including a resilient part adapted to trail said armclosely adjacent the top of said packing to substantially confine liquiddischarged from said slot to the top surface of said packing.

3. Gas and liquid contact apparatus according to claim 2 in which thebafiie means include a plate secured to said arm having a downwardlybent portion the end of which in operation is adjacent the top surfaceof the packing.

4. Gas and liquid contact apparatus according to claim 1 in which adeflector plate is provided in the arm adjacent the slot and proximatethe axis about which the arm rotates to assure that the packing mostproximate the axis about which the arm rotates is moistened.

References Cited in the file of this patent UNITED STATES PATENTS678,979 Ridgway July 23, 1901 997,058 Ham July 4, 1911 2,029,268 LundJan. 28, 1936 2,335,281 Jepson Nov. 30, 1943 2,595,702 Prevost May 6,1952 2,692,163 Geel Oct. 19, 1954 2,809,818 Munters Oct. 15, 19572,852,311 Alexeff Sept. 16, 1958 2,895,683 Dvorak July 21, 19592,919,861 Meek Jan. 5, 1960 2,921,748 Kane Jan. 19, 1960 3,002,700Mohring Oct. 3, 1961 FOREIGN PATENTS 105,885 Sweden Nov. 10. 1942

1. IN A GAS AND LIQUID CONTACT APPARATUS, THE COMBINATION OF A PACKINGMEAN FOR PASSING A GAS STREAM THROUGH SAID PACKING, LIQUID SUPPLY MEANS,AND MEANS FOR DISTRIBUTING THE LIQUID OVER SAID PACKING TO FLOWTHERETHROUGH IN CONTACT WITH THE GAS STREAM PASSING THERETHROUGH, SAIDDISTRIBUTING MEANS COMPRISING A SPRAYER ROTATABLY MOUNTED ABOVE SAIDPACKING ADJACENT THE TOP THEREFORE, MEANS FOR ROTATABLY MOUNTING SAIDSPRAYER, SAID SPRAYER INCLUDING A TUBULAR ARM HAVING A SLOT THEREINEXTENDING SUBSTANTIALLY THE LENGTH THEREOF AND PLACED IN THE LOWERPORTION THEREOF TO DISCHARGE LIQUID FROM THE ARM TOWARD THE PACKING,SAID LIQUID SUPPLY MEANS COMMUNICATING WITH THE INTERIOR OF SAID TUBULARARM, AND ADJUSTMENT MEANS FOR TAPERING THE WIDTH OF SAID SLOT TOWARD THEAXIS OF ROTATION OF THE SPRAYER WHEREBY THE LIQUID DISCHARGE FROM SAIDSLOT IS UNIFORMLY DISTRIBURED OVER THE TOP OF THE PACKING, SAIDADJUSTMENT MEANS INCLUDING A PLURALITY OF BOLT MEANS SPACED FROM EACHOTHER LONGITUDINALLY OF THE ARM FOR ADJUSTING THE WIDTH OF THE SLOT.